/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.update.processor;

import org.apache.solr.common.util.NamedList;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.response.SolrQueryResponse;

/**
 * Trims leading and trailing whitespace from any CharSequence values found in
 * fields matching the specified conditions and returns the resulting String.
 * <p>
 * By default this processor matches all fields
 * </p>
 * 
 * <p>
 * For example, with the configuration listed all String field values will have
 * leading and trailing spaces removed except for fields whose named ends with "
 * <code>_literal</code>".
 * </p>
 * 
 * <pre class="prettyprint">
 * &lt;processor class="solr.TrimFieldUpdateProcessorFactory"&gt;
 *   &lt;lst name="exclude"&gt;
 *     &lt;str name="fieldRegex"&gt;.*_literal&lt;/str&gt;
 *   &lt;/lst&gt;
 * &lt;/processor&gt;
 * </pre>
 */
public final class TrimFieldUpdateProcessorFactory extends
		FieldMutatingUpdateProcessorFactory {

	@SuppressWarnings("unchecked")
	@Override
	public void init(NamedList args) {
		// no trim specific init args
		super.init(args);
	}

	@Override
	public UpdateRequestProcessor getInstance(SolrQueryRequest req,
			SolrQueryResponse rsp, UpdateRequestProcessor next) {
		return new FieldValueMutatingUpdateProcessor(getSelector(), next) {
			protected Object mutateValue(final Object src) {
				if (src instanceof CharSequence) {
					return ((CharSequence) src).toString().trim();
				}
				return src;
			}
		};
	}
}
